A haymaking machine of this type permits two different types of operation, namely tedding and swathing. Such haymaking machines are therefore also called "universal" haymaking machines.
During tedding, the two raking wheels are located at the same height transversely to the direction of travel. Thus, the prongs assume a radial position relative to the axes of rotation of the raking wheels, and the tips of the prongs of the two raking wheels overlap. In this type of operation of the haymaking machine, the raking wheels are driven in opposite senses, so that the harvested crop is drawn in towards the center and is spread out broadly to the rear.
During swathing, the raking wheels are adjusted obliquely to the direction of travel and are driven in the same sense. The prongs are pivoted into a more tangential position relative to the raking wheels. As a result, in particular, the overlapping of the prongs is eliminated. The raking wheel lying at the front in a direction of travel transfers the raked-together harvest crop to the raking wheel lying further behind and offset. This raking wheel then rakes to the side all the harvest crop which is obtained, so that a side swath is formed by means of a swath shaper, for example a rubber flap or the like.
Whereas, during tedding, the raking wheels must be driven in opposite directions, it is absolutely essential, during swathing, that the two raking wheels be driven in the same direction. Because of the different directions of rotation of the raking wheels, considerable problems arise when conventional spring prongs terminating in coiled ends are used. For reasons of strength, the prongs should be stressed only in such as way that these coils tighten. To solve this problem, it has already been proposed (see Austrian Patent Application No. 3833/76) to arrange the prong-supporting part so that it can pivot through 180.degree. and can be locked in its end positions, to ensure that the spring coils located at the end of the prong tighten in any direction of rotation of the raking wheel. As has been shown in practice, however, the adjustment work necessary for this purpose, especially when it has to be carried out individually, is felt to be irksome by the operator.